One of the most common manifestations of diabetes mellitus is damage to the peripheral nervous system, known as diabetic neuropathy. While the precise mechanism responsible for the development of neuropathy has yet to be elucidated, it is mostly likely mediated by a variety of metabolic responses. Increasing attention has been directed at studying molecules that mediate growth and survival of the nerves, and has focused on some classical proteins such as nerve growth factor. We believe an additional group of mediators, known as cytokines, are also involved in this process. We are interested in a specific family of cytokines, the neuropoietic cytokine family, because its members are known to be expressed by both the nervous and immune systems and in the peripheral nervous system, at least three members of this family are important in the response to injury and repair in normal animals. We will investigate cytokine expression during the onset of neuropathy and in response to nerve injury. In addition, we will ask whether nerve regeneration is altered by administration of these cytokines. This could have obvious health benefits to the millions of diabetics that suffer from nerve damage.